Recently, the Internet has become popular, leading to an increase in the number of users who exchange various data with other users over the Internet.
However, for example, when a user wishes to send a certain image to an apparatus of another user, it has been the case that mutual connection is essentially prohibited due to difference between the capabilities of an own apparatus of the user and the apparatus of another user, resulting in a failure in transmitting image data.
In order to prevent this situation, a user must check the capability of a device at the other end in advance.
For example, in the case of streaming, as a method of exchanging streaming parameters between a server and a client, RTSP (Real Time Streaming Protocol) (Real Time Streaming Protocol, IETF RFC 2326, April 1998, <http://www.ietf.org/rfc/rfc/2326.txt>) describes use of SDP (Session Description Protocol) (SDP: Session Description Protocol, IETF RFC 2327, April 1998, <http://www.ietf.org/rfc/rfc/2327.txt>).
However, these documents do not define a specific procedure for exchanging parameters, raising difficulty in exchanging data reliably with each other.